Engineering performance of tungsten network reinforced copper matrix composites synthesized by selective laser melting and infiltration.

To solve poor engineering performance of copper-tungsten alloys operated at high temperatures, 3D network tungsten frameworks were prepared using a selective laser melting (SLM) process, and then copper was melted and diffused into these tungsten network structures to form copper matrix composites with different copper contents (i.e. Cu-10vol%W and Cu-30vol%W). Their mechanical/electrical properties and arc ablation performance were characterized. Results showed the obtained CuW composites were dense with good interfacial bonding, and the connected Cu phases formed a heat conduction channel and improved electrical and thermal conductivities of the composites. Electrical conductivities of Cu-30W and Cu-10W composites were 44.7% and 80.3% IACS, and their thermal conductivities at 25°C were 247.5 and 375.4 W/(m·K), respectively. The W-skeleton grid structure in the composites showed enhanced effects on impact toughness and anti-friction/wear resistance. Tensile strengths of Cu-30W and Cu-10W composites measured at 300°C were 95 MPa and 135 MPa, and their impact toughness values were 11.25 and 15.25 J/cm2, respectively. For the arc ablation performance, the copper phase of CuW composite was identified as the key influencing phase, whereas the W skeleton effectively hindered the spread of arc spots, inhibited quick melting of copper phases, and played effective support and protection functions.

W network reinforced Cu matrix composites were prepared by combining 3D printing technology and fusion technology, which significantly improved the thermal and mechanical properties of Cu matrix composites. We find that the interconnected Cu phases improves the thermal properties of the composites, and the mesh W skeleton improves the mechanical properties.

Ultrasensitive Visual Tracking of Toxic Cyanide Ions in Biological Samples Using Biocompatible Metal-Organic Frameworks Architectures.

The extraordinary accumulation of cyanide ions within biological cells is a severe health risk. Detecting and tracking toxic cyanide ions within these cells by simple and ultrasensitive methodologies are of immense curiosity. Here, continuous tracking of ultimate levels of CN--ions in HeLa cells was reported employing biocompatible branching molecular architectures (BMAs). These BMAs were engineered by decorating colorant-laden dendritic branch within and around the molecular building hollows of the geode-shelled nanorods of organic-inorganic Al-frameworks. Batch-contact methods were utilized to assess the potential of hollow-nest architecture for inhibition/evaluation of toxicant CN--ions within HeLa cells. The nanorod BMAs revealed significant potential capabilities in monitoring and tracking of CN- ions (88 parts per trillion) in biological trials within seconds. These results demonstrated sufficient evidence for the compatibility of BMAs during HeLa cell exposure. Under specific conditions, the BMAs were utilized for in-vitro fluorescence tracking/sensing of CN- in HeLa cells. The cliff swallow nest with massive mouths may have the potential to reduce the health hazards associated with toxicant exposure in biological cells.

Metal-organic framework-derived trimetallic oxides with dual sensing functions for ethanol.

Metal-organic framework (MOF)-derived metal oxide semiconductors have recently received extensive attention in gas sensing applications due to their high porosity and three-dimensional architecture. Still, challenges remain for MOF-derived materials, including low-cost and facile synthetic methods, rational nanostructure design, and superior gas-sensing performances. Herein, a series of Fe-MIL-88B-derived trimetallic FeCoNi oxides (FCN-MOS) with a mesoporous structure were synthesized by a one-step hydrothermal reaction followed by calcination. The FCN-MOS system consists of three main phases: α-Fe2O3 (n-type), CoFe2O4, and NiFe2O4 (p-type), and the nanostructure and pore size can be controlled by altering the content of α-Fe2O3, CoFe2O4, and NiFe2O4. The sensors based on FCN-MOS exhibit a high response of 71.9, a good selectivity towards 100 ppm ethanol at 250 °C, and long-term stability up to 60 days. Additionally, the FCN-MOS-based sensors show a p-n transition gas sensing behavior with the alteration of the Fe/Co/Ni ratio.

Highly Sensitive and Selective Surface Acoustic Wave Ammonia Sensor Operated at Room Temperature with a Polyacrylic Acid Sensing Layer.

In this study, polyacrylic acid (PAA) films were deposited onto a quartz surface acoustic wave (SAW) resonator using a spin-coating technique for ammonia sensing operated at room temperature, and the sensing mechanisms and performance were systematically studied. The oxygen-containing functional groups on the surfaces of the PAA film make it sensitive and selective to ammonia molecules, even when tested at room temperature. The ammonia molecules adsorbed by the oxygen-containing functional groups of PAA (e.g., hydroxyl and epoxy groups) increase the membrane's stiffness, which was identified as the primary mechanism leading to the positive frequency shifts. However, mass loading due to adsorption of ammonia molecules is not a major reason as it will result in a negative frequency shifts. When the PAA coated SAW sensor was exposed to ammonia with a low concentration of 500 ppb, it showed a positive frequency shift of 225 Hz, with both good repeatability and stability, as well as a good selectivity to ammonia compared with those to C2H5OH, H2, HCl, H2S, CO, NO2, NO, and CH3COCH3.

Nitrogen-doped carbon hollow trunk-like structure as a portable electrochemical sensor for noradrenaline detection in neuronal cells.

To date, the production and development of portable analytical devices for environmental and healthcare applications are rapidly growing. Herein, a portable electrochemical sensor for monitoring of noradrenaline (NA) secreted from living cells using mesoporous carbon-based materials was fabricated. The modification of the interdigitated electrode array (IDA) by nitrogen-doped mesoporous carbon spheres (N-doped MCS) and nitrogen-doped carbon hollow trunk-like structure (N-doped CHT) was used to fabricate the NA sensor. The N-doped CHT surface shows multiple holes distributed with micrometer-sized open holes (1-2 µm) and nanometer-sized thin walls (∼98 nm). The N-doped CHT surface heterogeneity of wrinkled and twisted hollow trunk structures improve the diffusion pathway and the NA molecules loading. The N-doped CHT/IDA showed a highly selective assay for monitoring of NA with high sensitivity (1770 µA/µM × cm2), a low detection limit (0.005 µM), and a wide linear range (0.01-0.3 µM). The N-doped CHT/IDA monitored the NA secreted from PC12 cells under various concentrations of simulation agents (KCl). The designed N-doped CHT/IDA provides a portable NA-sensor assay with facile signaling, good stability, high biocompatibility, in-vitro assay compatibility, and good reproducibility. Therefore, the designed sensor can be used as a portable sensor for NA detection in live cells and can be matched with portable smartphones after further developments.

Non-metal sensory electrode design and protocol of DNA-nucleobases in living cells exposed to oxidative stresses.

Sensory protocols for evaluation of DNA distortion due to exposure to various harmful chemicals and environments in living cells are needed for research and clinical investigations. Here, a design of non-metal sensory (NMS) electrode was built by using boron-doped carbon spherules for detection of DNA nucleobases, namely, guanine (Gu), adenine (Ad), and thymine (Th) in living cells. The key-electrode based nanoscale NMS structures lead to voids with a facile diffusion, and strong binding events of the DNA nucleobases. Furthermore, the NMS geometric structures would significantly create electrode surfaces with numerous centrally active sites, curvature topographies, and anisotropic spherules. The NMS shows potential as sensitive protocol for DNA-nucleobases in living cells exposed to oxidative stresses. In one-step signaling assay, NMS shows high signaling transduction of Gu-, Ad-, and Th-DNA nucleobases targets with ultra-sensitive and low detection limits of 3.0, 0.36, and 0.34 nM, respectively, and a wide linear range of up to 1 µM. The NMS design and protocol show evidence of the role of surface construction features and B-atoms incorporated into the graphitic carbon network for creating abundant active sites with facile electron diffusion and heavily target loads along with within-/out-plane circular spheres. Indeed NMS, with spherule-rich interstitial surfaces can be used for sensitive and selective evaluation of damaged-DNA to various dysfunctional metabolism in the human body.

Progress in biomimetic leverages for marine antifouling using nanocomposite coatings.

Because of the environmental and economic casualties of biofouling on maritime navigation, modern studies have been devoted toward formulating advanced nanoscale composites in the controlled development of effective marine antifouling self-cleaning surfaces. Natural biomimetic surfaces have the advantages of micro-/nanoroughness and minimized free energy characteristics that can motivate the dynamic fabrication of superhydrophobic antifouling surfaces. This review provides an architectural panorama of the biomimetic antifouling designs and their key leverages to broaden horizons in the controlled fabrication of nanocomposite building blocks as force-driven marine antifouling models. As primary antifouling designs, understanding the key functions of surface geometry, heterogeneity, superhydrophobicity, and complexity of polymer/nanofiller composite building blocks on fouling-resistant systems is crucial. This review also discusses a wide range of fouling release coating systems that satisfy the growing demand in a sustainable future environment. For instance, the integration of block, segmented copolymer-based coatings and inorganic-organic hybrid nanofillers enhanced the model's antifouling properties with mechanical, superhydrophobic, chemically inert, and robust surfaces. These nanoscale antifouling systems offered surfaces with minimized free energy, micro-/nanoroughness, anisotropic heterogeneity, superior hydrophobicity, tunable non-wettability, antibacterial efficiency, and mechanical robustness. The confined fabrication of nanoscale orientation, configuration, arrangement, and direction along the architectural composite building blocks would yield excellent air-entrapping ability along the interfacial surface grooves and interfaces, which optimized the antifouling coating surfaces for long-term durability. This review provides systematic evidence of the effect of structurally folded nanocomposites, nanofiller tectonics, and building blocks on the creation of outstanding superhydrophobicity, self-cleaning surfaces, and potential antifouling coatings. The development of modern research gateways is a candidate for the sustainable future of antifouling coatings.

Three-Dimensional Circular Surface Curvature of a Spherule-Based Electrode for Selective Signaling and Dynamic Mobility of Norepinephrine in Living Cells.

A highly sensitive protocol for signaling norepinephrine (NEP) in human fluids and neuronal cell line models should be established for clinical investigation of some neuronal diseases. A metal-free electrode catalyst was designed based on a sulfur-doped carbon spheroidal surface (S-CSN) and employed as a transducing element for selective signaling of NEP in biological samples. The designed electrode of S-CSN features a spherical construct and curvature surface to form a spheroidal nanolayer with an average layer size of <2 nm. S-CSN shows surface topography of a circular surface curvature with a rugged surface texture, ridge ends, and free open spaces between interlayers. The rich-space diversity surfaces offer highly active surface with facile molecular/electron diffusion, multi-diffusive centers, and high target loading along with in-/out-of-plane circular spheres of the S-CSN surface. The active doping of S atoms onto the carbon-based electrode creates an active transducing element with many active sites, strong binding to targeted molecules, facile diffusion of charges/molecules, long-term durability, and dense reactive exposure sites for signaling NEP at ultratrace levels. S-CSN could be a sensitive and selective nanosensor for signaling NEP and establishing a sensing protocol with high stability and reproducibility. The sensory protocol based on S-CSN exhibits high sensitivity and selectivity with a low detection limit of 0.001 µM and a wide linear range of 0.01-0.8 µM. The in vitro sensory protocol for NEP secreted from living cells (neuronal cell line model) under stimulated agents possesses high sensitivity, low cytotoxicity, and high biocompatibility. These results confirm the successful establishment of NEP sensor in human blood samples and neuronal cells for clinical investigation.

Longitudinal Hierarchy Co3O4 Mesocrystals with High-dense Exposure Facets and Anisotropic Interfaces for Direct-Ethanol Fuel Cells.

Novel electrodes are needed for direct ethanol fuel cells with improved quality. Hierarchical engineering can produce catalysts composed of mesocrystals with many exposed active planes and multi-diffused voids. Here we report a simple, one-pot, hydrothermal method for fabricating Co3O4/carbon/substrate electrodes that provides control over the catalyst mesocrystal morphology (i.e., corn tubercle pellets or banana clusters oriented along nanotube domains, or layered lamina or multiple cantilevered sheets). These morphologies afforded catalysts with a high density of exposed active facets, a diverse range of mesopores in the cage interior, a window architecture, and vertical alignment to the substrate, which improved efficiency in an ethanol electrooxidation reaction compared with a conventional platinum/carbon electrode. On the atomic scale, the longitudinally aligned architecture of the Co3O4 mesocrystals resulted in exposed low- and high-index single and interface surfaces that had improved electron transport and diffusion compared with currently used electrodes.